This invention relates to polyphosphazene copolymers containing repeating ##STR2## units in the polymer chain in which acetylenic substituents are attached to the phosphorus atom. More particularly, the invention relates to polyphosphazene copolymers containing an acetylenic substituent and a substituted or unsubstituted alkoxy, aryloxy, amino or mercapto substituent.
Polyphosphazene homo- and co- polymers containing repeating ##STR3## units in which various alkoxy, substituted alkoxy, aryloxy and substituted aryloxy groups are attached to the phosphorus atom and their method of preparation are described in the prior art as illustrated in the publication "Phosphorus-Nitrogen Compounds", Academic Press, New York, New York 1972 by H. R. Allcock and "Poly(Organophosphazenes)", Chemtech, Sept. 19, 1975 by H. R. Allcock and in such U.S. Pat. Nos. as 3,515,688; 3,702,833; and 3,856,712.